# Molecular tools for precise manipulation of defined synaptic connections

> **NIH NIH R01** · STANFORD UNIVERSITY · 2024 · $1,405,618

## Abstract

Project Summary/Abstract
 Our project will address a major gap in existing neuroscience research tools, through the development of
intersectional genetic tools for drug-controlled manipulation of specific synaptic connections between two
genetically- or anatomically-defined neuronal populations. The tools we have engineered build from established cell
manipulation tools – DREADDs, PSAMs, and tetanus toxin – but critically, introduce trans-synaptic gating. Thus,
the tools become activatable only at user-selected, genetically-defined cell-cell contact sites. We propose to develop
three tool platforms in Aims 1-3, which enable drug-controlled synapse manipulation by three different mechanisms
and on three different timescales – ranging from seconds to minutes for antigen-gated PSAM ion channels to hours
for antigen-gated trans-tetanus toxin. We have designed the antigen-gating of our tools to be both modular and
programmable, so that either exogenous (e.g., surface GFP) or endogenous (e.g., tumor marker GD2) trans-synaptic
triggers can be used. To develop and optimize these tools, we will rely on the extensive protein engineering and
directed evolution expertise of PI Alice Ting, who has previously developed proximity labeling enzymes and calcium
integrators that are widely used in the neuroscience community.
 We will carefully validate the tools in two distinct mouse brain regions in the labs of PIs Xiaoke Chen and
Ivan Soltesz. Chen will evaluate the specificity and sensitivity of the proposed tools by assessing their ability to
thoroughly and selectively silence connections from the paraventricular thalamus and prefrontal cortex onto two types
of nucleus accumbens medium spiny neurons. We will use a combination of electrophysiological recording and
optogenetic pathway stimulation and calcium imaging on ex vivo brain slices to read out drug-gated inhibition of
these circuits. We will then utilize these tools in vivo to study the circuit mechanisms of opioid withdrawal and
cocaine-induced behavioral sensitization. In the Soltesz lab, we plan to apply the tools to answer previously untestable
questions about the roles of cell-type specific projections in regulating hippocampal function across scales from local
microcircuits to long-range inputs. Our hippocampal experiments will use single cell electrophysiology, optogenetics,
in vivo imaging of behavior-associated neuronal activity, local field potential recordings and behavioral memory tests.
Constant feedback between these ex vivo and in vivo studies and the tool engineering efforts in Aims 1-3 will ensure
that our tools are optimized for maximal efficacy, specificity, and robustness.
 Our team is highly interdisciplinary and diverse, combining the chemical biology and protein engineering
expertise of Alice Ting with the systems and molecular neuroscience expertise of Xiaoke Chen and Ivan Soltesz.
Soltesz is a pioneer in exploring the roles of hippocampal neuronal subpopulations in normal and path...

## Key facts

- **NIH application ID:** 10862486
- **Project number:** 1R01MH135934-01
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Xiaoke Chen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $1,405,618
- **Award type:** 1
- **Project period:** 2024-07-01 → 2027-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10862486

## Citation

> US National Institutes of Health, RePORTER application 10862486, Molecular tools for precise manipulation of defined synaptic connections (1R01MH135934-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10862486. Licensed CC0.

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